Step by Step Guide to Building a OneNote API Integration in C#

Aug 2, 2024 • 5 minute read

Introduction

Hey there, fellow developer! Ready to dive into the world of OneNote API integration? You're in for a treat. We'll be using the Microsoft.Graph package to tap into OneNote's powerful capabilities. Buckle up, and let's get coding!

Prerequisites

Before we jump in, make sure you've got:

Visual Studio (or your favorite C# IDE)
.NET Core SDK
An Azure account for app registration

Got all that? Great! Let's move on.

Setting up the project

First things first, let's create a new C# project. Fire up Visual Studio, create a new console app, and then grab the Microsoft.Graph NuGet package:

Install-Package Microsoft.Graph

Easy peasy, right?

Authentication

Now for the fun part - authentication. We'll use the Microsoft Authentication Library (MSAL) to get our access token. Here's a quick snippet to get you started:

var scopes = new[] { "Notes.ReadWrite.All" };
var clientId = "YOUR_CLIENT_ID";
var clientSecret = "YOUR_CLIENT_SECRET";
var tenantId = "YOUR_TENANT_ID";

var confidentialClientApplication = ConfidentialClientApplicationBuilder
    .Create(clientId)
    .WithTenantId(tenantId)
    .WithClientSecret(clientSecret)
    .Build();

var authResult = await confidentialClientApplication.AcquireTokenForClient(scopes).ExecuteAsync();

Initializing GraphServiceClient

With our token in hand, let's set up our GraphServiceClient:

var graphClient = new GraphServiceClient(
    new DelegateAuthenticationProvider(
        async (requestMessage) =>
        {
            requestMessage.Headers.Authorization = 
                new AuthenticationHeaderValue("Bearer", authResult.AccessToken);
        }));

Basic OneNote operations

Now we're cooking! Let's retrieve some notebooks:

var notebooks = await graphClient.Me.Onenote.Notebooks
    .Request()
    .GetAsync();

Creating a new notebook? No sweat:

var notebook = new Notebook
{
    DisplayName = "My Awesome Notebook"
};

await graphClient.Me.Onenote.Notebooks
    .Request()
    .AddAsync(notebook);

Working with page content

Time to add some pages with actual content:

var page = new OnenotePage
{
    Title = "My First Page",
    Content = "<html><head><title>My First Page</title></head><body><p>Hello, OneNote!</p></body></html>"
};

await graphClient.Me.Onenote.Notebooks[notebookId].Sections[sectionId].Pages
    .Request()
    .AddAsync(page);

Handling attachments

Got files to add? No problem:

using (var stream = new System.IO.FileStream("path/to/file.pdf", FileMode.Open))
{
    await graphClient.Me.Onenote.Pages[pageId].Resources
        .Request()
        .AddAsync(stream, "file.pdf");
}

Advanced operations

Feeling adventurous? Let's search for some content:

var result = await graphClient.Me.Onenote.Pages
    .Request()
    .Filter("title eq 'My First Page'")
    .GetAsync();

Error handling and best practices

Remember, always wrap your calls in try-catch blocks and respect those rate limits. The API gods will thank you!

try
{
    // Your API call here
}
catch (ServiceException ex)
{
    Console.WriteLine($"Error making API call: {ex.Message}");
}

Conclusion

And there you have it! You're now armed and dangerous with OneNote API integration skills. Remember, this is just the tip of the iceberg. There's so much more you can do, so keep exploring and building awesome stuff!

For more in-depth info, check out the official Microsoft Graph documentation. Now go forth and conquer the world of OneNote integration!